At the site of America's deadliest avalanche, witnesses report bizarre apparitions and sickly feelings of dread. Phil and Jess venture deep into Washington's Cascade Mountains to investigate a shocking cover-up and test a mind-bending scientific theory.

Deep in the Peruvian jungle, where deadly wildlife lurks at every turn, a supersized beast is terrifying locals. Phil tracks what could be an unknown species, while Jess hunts for evidence that a legendary creature known as Yacumama is on the hunt.